P1490: CHILDREN WITH SICKLE CELL DISEASE AND MOYAMOYA SYNDROME: A 10-YEAR EXPERIENCE
Authors: A. Pina Monteiro, A. R. Henriques, M. Mota, C. Salgado, J. Coelho, S. Quintas, M. J. Palaré, A. Ferrão
Journal: HemaSphere (2022)

Background: Sickle cell anemia (SCD) is a multiorgan disease. Involvement of the central nervous system (CNS) is associated with increased mortality. Cerebrovascular accidents, especially when associated with permanent neurological deficits, are one of the most devastating potential outcomes of SCD. SCD can be complicated by Moyamoya syndrome (MMS), which is characterized by progressive stenosis of the supraclinoid segment of carotid arteries and development of typical collaterals, resulting in increased risk for both ischemic and hemorrhagic strokes. Aims: We describe the clinical characteristics of children with SCD and MMS treated at our center over the last 10 years and define the prevalence of MMS in our setting. Methods: We conducted a retrospective, descriptive study of all patients with SCD who were diagnosed with cerebrovascular disease and with MMS in our institution from 2012 to 2021. Indications for neuroimaging [(magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA)] in our center include recurrent episodes of syncope, epileptic seizures, neurocognitive changes, time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries (ICA) measured ≥200 cm/s or before starting regular transfusion regime. Relevant clinical data was collected and summarized using descriptive statistics. Results: The study included 109 patients with SCD and 19,3% of them (21 patients) required neuroimaging. Within these patients, 6 presented with acute focal neurological signs that resulted in a diagnosis of ischemic stroke in four patients, and posterior reversible encephalopathy syndrome diagnosis in the other two. Besides these, 2 patients (9,5%) were diagnosed by neuroimaging with MMS and 1 (4,8%) had a pattern suggestive of MMS on brain MRI not confirmed by angiography. Furthermore, whereas four (19%) patients had no imaging findings suggestive of cerebrovascular disease, they presented with TAMMV ≥200cm/s, so they were proposed to regular transfusion regimen for primary prevention of stroke. Regarding the patients diagnosed with SCD and MMS, MMS was diagnosed at 9 years old in one patient and at 10 years old in another. Both patients had a SS genotype and were diagnosed following an abnormal surveillance transcranial doppler study, since they were asymptomatic for the disease. One of the patients was under erythrocytapheresis protocol and achieved a HbS level <20%. Currently she is without critical stenosis or cerebrovascular events, maintaining only imaging follow-up. The other patient was under regular transfusion regimen with HbS levels between 40 and 50%, and has been proposed for sibling bone marrow transplantation and encephaloduroarteriosynangiosis. Summary/Conclusion: The prevalence of MMS in our center (1,8%) is lower than described in other studies. Recent guidelines recommend at least a one-time MRI screening in early-school-age children to detect cerebrovascular disease earlier and reduce the burden of CNS complications in children and adults with SCD. By following these new recommendations, we expect an earlier and more frequent diagnosis of MMS, thus reducing the morbidity of these patients.